rlange - 1:09 pm on Mar 21, 2012 (gmt 0)
Browsers doesn't send referer data on HTTPS pages.
That's really only when going from secure to non-secure. Still...
Checking the 2012 access logs for one of my company's sites, I see a number of HTTPS referrals from google.com. Some of them (from January and early February) include the complete referring URL (even the search query). Since about the last week of February, though, they've been just "https://www.google.com/".